Currently, in order to solve problems of signal shielding caused by shell, electronic products, such as metal cell phone, mostly adopt a method of slotting on a rear cover of the cell phone and then injection molding. For example, HTC ONE has an upper and a lower antenna slots, iPhone 5/5s has a side antenna slot, etc. However, the method of slotting an antenna slot on electronic product metal shell (for example, rear cover of the metal cell phone) and then injection molding stated above may cause some damages to the whole structure of the electronic product metal shell, and affect cleanliness and integrity of appearance of the electronic product metal shell. Meanwhile, a visible plastic of the electronic product metal shell (for example, rear cover of the metal cell phone) would also damage a metal texture of the whole electronic product metal shell.